Martian dust reveals water content in ancient times

Washington: Mars rover Curiosity has more than 120,000 measurements of surface rocks and soil and in the process revealed a more detailed image of how much water was once present on the Red Planet.

Celia Arnaud, a senior editor at C and EN, notes that Curiosity has traveled nearly 4 miles since it landed in 2012 and is more than halfway to its destination, Mount Sharp.
But in the meantime, its onboard equipment is collecting a treasure trove of information about the Red Planet`s surface. The rover is equipped with an instrument called ChemCam, short for "Chemistry and Camera." It not only snaps high-resolution images of the barren landscape it passes, but also can figure out what`s in the soil and rocks within about 23 feet of its location.

Scientists back on Earth, at NASA`s Jet Propulsion Lab, aim the ChemCam at targeted rocks and zap them with a laser beam. The instrument reads the light that bounces back and can tell what atoms and molecules are in the rocks.
Scientists have found that the weight of the dust they`ve sampled is 2 to 4 percent water. And for the first time, they have confirmed that the common element fluorine exists on Mars.

The article has been published in Chemical and Engineering News (C and EN).